Screening in pregnancy

For information on screening tests for you and your baby in multiple languages, please click here. 

SASH Maternity Services will offer you a number of screening and diagnostic tests during your pregnancy.  Your midwife will advise you which tests are offered and why.  These tests can help you find out about your own health and the health of your baby before birth.

All of the tests are optional – it’s your choice whether to have the test or not.  The information these tests can provide will help you make choices about your pregnancy, and help your midwife and doctor to provide the best care possible for you and your baby during your pregnancy, the birth and once baby has been born.

You will be asked to consent to the test with information shared face-to-face at each appointment.

Please also see the NHS patient information resource.

The diagram below explains what tests will be performed, and at which stage of the pregnancy:

Click to expand image

Screening blood tests

We offer all pregnant people blood tests in the early stages of pregnancy to check for a number of problems. We recommend these blood tests are taken before 10 weeks of pregnancy. Your haemoglobin is checked for signs of anaemia (low iron levels) and your blood group and Rhesus factor. We would also recommend screening for the following:

  • Infectious diseases including Hepatitis B, HIV and syphilis as these infections can cause harm to you or your baby without treatment. If an infection is found, you will be offered specialist care to ensure you and your baby has the correct support and treatment.
  • We offer screening for rubella susceptibility (German measles) to identify those who are not protected against rubella. If you are found not to be protected we will offer you a vaccination after the birth of your baby before you leave the hospital. This will help protect you in future pregnancies.
  • Sickle Cell and Thalassaemia: these are inherited disorders of the red blood cells. Anyone can carry a gene for one of these conditions but they are more common in people whose ancestors or blood relatives come from certain parts of the world. If your family origin is one from a high risk area you will be offered haemoglobinopathy screening.  If you are found to carry an unusual haemoglobin gene we will discuss this with you, and will offer your baby’s biological father the same test to see if he carries a similar gene.

Your scans

While we know that your scans are such a special opportunity to enjoy seeing your baby moving and growing inside your body, it is important that you also understand that they are also screening tests that you are consenting to on attendance.  We love sharing these special moments with you, and are also looking to ensure you and your baby are safe and well.

  • Nuchal scan
    • Your first scan, the early pregnancy scan or nuchal scan, will be between 11 and 14 weeks of pregnancy and is the first opportunity to see your baby’s heart beating. At this scan we will confirm the number of babies and the estimated due date of your baby(ies) birth.
    • Importantly, this scan is also a screening test for Trisomy 21, 18 and 13 – Down’s syndrome, Edward’s syndrome and Patau’s syndrome. SASH Maternity offers the combined screening tests between 11 +2 weeks up to 14+1 weeks of pregnancy.   It is called a combined test because your risk is calculated using signs tested in the scan, combined with a blood test.  The results of this screening test will give you a risk factor and are not diagnostic.  These are normally available within two working days.
    • If you receive a “high chance” result, you will be offered diagnostic tests to provide a definite result about your baby’s chromosomes. For more information and support for “high chance” results, see: the arc website,,uk and the soft website.
    • If you are unable to have a test before 14 weeks pregnancy, SASH Maternity also offers you the quadruple or quad test as an alternative to the combined test.
    • Please note: after 20 weeks of pregnancy, the screening options for you are limited. To discuss further, please contact the antenatal screening midwives either on: 01737 768511 Ext 6977 or their email on
  • Anomaly scan
    • At around 20 weeks pregnancy you will have a second routine screening scan. This scan allows us to assess the baby’s physical development where we will specifically look at their heart structures; their brain; their spine; their stomach; kidneys; bladder and bones.
    • We are also looking at your baby’s placenta, its location, size and position. In some personalised care plans we will also be looking at your placenta’s blood flow
    • At this scan we may be able to tell you your baby(ies) gender.
  • Additional scans
    • All women are offer the two routine Nuchal and Anomaly scans.
    • Some women may require additional scans, for example women expecting twins, triplets, who have diabetes, smoke, are obese or very underweight.
    • Your midwife will advise you of your personalised care plan to include your scans when you meet at your first appointment. Changes during your pregnancy may mean that this personalised care plan is adjusted including a need for additional scans.
    • Additional scans will continue to measure baby(ies) growth and physical development as well as assessing your placental function.


For more information on scan results in pregnancy, see:


Diagnostic tests for fetal genetics (also known as invasive tests) are tests that will provide you with definite information about your baby’s chromosomes and confirm whether or not your baby has a chromosomal abnormality. All pregnant people who are assessed with a high likelihood or chance result from their combined or quadruple screening test will be offered a diagnostic test.  Those who have had a previously affected pregnant by a chromosomal problem or have a history of an inherited condition will also be offered a diagnostic test.

  • It is important to know that a diagnostic test carries a risk of miscarriage of 1 in 100, so you need to carefully consider if you would like to have the test or not.
  • All pregnant people who accept a diagnostic test will be referred to our tertiary centre at St George’s Hospital Fetal Medicine Unit. For more information, please click here. 
  • Most babies, even those with an increased risk following antenatal screening will have normal chromosomes. For those cases where we detect an actual problem a member of the antenatal screening  team will be in touch and will tell you what the problem and is and how it may affect your baby. You will be invited to meet with a member of the screening team and a fetal medicine consultant so we can discuss what options are available to you.
  • For more information and support see: the arc website,,uk and the soft website.

Non-invasive Prenatal Testing (NIPT)

  • The non-invasive prenatal testing (NIPT) is available privately at East Surrey Hospital. We offer the SAFE test- St George’s Antenatal Fetal Evaluation.
  • The SAFE test evaluates the chance of chromosomal condition in a pregnancy. It is a blood test available from 10 weeks of pregnancy with a greater than 99% detection rate of Trisomy 21 (Down’s syndrome), Trisomy 18 (Edwards’ Syndrome) and Trisomy 13 (Patau’s Syndrome).
  • A blood sample is taken from mum in the antenatal screening department at East Surrey Hospital. The sample is then sent to St George’s Hospital in London and the result is received on the online portal within 7-10 working days.
  • The cost of the test is £350. Please note, payment can only be made by card.
  • For up to date information on NIPT please go to
  • You can also visit the St George’s Hospital website for more information about the SAFE test.
  • To book a private NIPT at East Surrey Hospital please call the antenatal screening team on 01737 768 511 x6977 or email

Urine tests

Your midwife will routinely request a urine sample from you. They will use a urine analysis dip test in the room and then send the urine of to the laboratory for further testing. The results may indicate if a urine infection is present or any normal bacteria which can impact upon care at a later date, such as Group B strep.

Carbon Monoxide Monitoring

Carbon monoxide (CO) is a poisonous gas that has no smell or taste. Breathing in carbon monoxide can make you unwell and can be fatal if exposed to very high levels.

After the CO is breathed in, it enters the bloodstream and mixes with your red blood cells called haemoglobin. When this happens, the blood cell will no longer be able to carry oxygen.

CO is produced when tobacco products are burnt and is found in inhaled, exhaled and passive smoke.  CO can also be produced by exhaust fumes, poorly ventilated fossil or weed fuelled heating and cooking appliances.

It is important to understand your exposure to CO as it can be especially dangerous during pregnancy as it can reduce your baby’s access to oxygen which can slow their growth and development, increase the risk of miscarriage, stillbirth, sudden infant death and cause breathing issues for the first 6 months of their life.

For more information visit the One You Surrey website. 

For support to stop smoking, click here.


  • Whooping cough and flu vaccine These vaccinations are both research trial evidence based to be safe during pregnancy. We recommend that all pregnant women have these vaccinations to reduce their chance of becoming unwell during pregnancy and to give some protection to your unborn baby.
  • Testing for Sickle Cell and Thalassaemia: These are inherited blood disorders that mainly affect people whose ancestors come from Africa, the Caribbean, the Mediterranean, India, Pakistan, South and Southeast Asia and the Middle East. Pregnant people are offered screening tests for these disorders, but you can have a free blood test either from a GP or your local Sickle Cell and Thalassaemia Centre.

Useful resources

Antenatal results and choices logoAntenatal Results and Choices website
Down's syndrome association logoDown’s Syndrome Association
SOFT logoSOFT (Support Organisation for Trisomy 13 & 18)